Abstract: An optical element has a design wavelength ?, an optical axis and alternating refractive index changes along the optical axis. The alternating refractive index changes form three reflectors and two optical resonators for light of the design wavelength ? incident along the optical axis, wherein each of the resonators is arranged between two of the reflectors. At least one of the resonators includes a Kerr-active material; and the two optical resonators differ with regard to non-linear components IRes(i)·n2(i) of their total refractive indices n(i)=n0(i)+IRes(i)·n2(i) by at least 50% of the smaller one of the non-linear components in terms of absolute value, wherein IRes(i) is a resulting intensity of the light of the design wavelength ? that results within the respective resonator due to its arrangement between the respective reflectors, and wherein n2(i) is a non-linear refractive index of the respective resonator.